a(n) = Sum_{d|n} (d^2+1)^n.A367551a(n) = Sum_{d|n} (d^2+1)^n.Terms a(0) =2a(1) =29a(2) =1008a(3) =84162a(4) =11881408a(5) =2566742098a(6) =781250000128External referencesoeis: A367551